The present invention relates to a lifting magnet unit with a gripping mechanism to be hung on a crane for lifting and transporting used articles recovered for recycling from industrial waste, dismantled machines and broken buildings and structures.
The elemctromagnetic attraction of a conventional lifting magnet decreases due to the reduction of the current that flows through the solenoid resulting from increase in the resistance of the solenoid when the temperature of the solenoid rises. Accordingly, the lifting capacity of the lifting magnet varies greatly depending on the variation of the ambient temperature. The variation of the lifting capacity of the lifting magnet is remarkable particularly in lifting junk including miscellaneous articles of various materials, such as domestic waste articles including electric washing machines and electric fans, dismantled automotive bodies, disassembled light shape steels and entangled reinforcing bars of broken reinforced concrete structures. There are two ordinary means for lifting and transporting such articles and materials hard to handle, namely, employing, in combination, a crane equipped with a lifting magnet and a crane equipped with a gripping mechanism, and alternately and selectively using a lifting magnet and a gripping mechanism on a single crane according to the purpose.
Among such conventional means, the former requires an increased investment in two cranes, while the latter requires much time and work for replacing the lifting magnet and the gripping mechanism, and hence effective working time is reduced. Furthermore, the installation of two individual cranes in a narrow working space makes lifting and transporting work difficult.